IPCC Expert Meeting on Geoengineering

Annex 5: Breakout Group Reports
Table A.5.2: Criteria for Carbon Dioxide Removal Approaches
Ocean
uptake,
biological
Ocean
uptake,
chemical
Afforestation;
Reforestation
Biochar;
Bio-
Storage
Air
Capture
Weathering
on land
Ethi cal
Arguments
Feasibili ty
Effecti veness
Si de-effects
Effi ci ency
(“ Social cost” ,
including sideeffects)
Regulation (legal
aspects)
Regulation
(policies and
instruments)
Monitoring /
Verification
Soci al
Acceptability
The group discussed the value of the criteria shown in the matrix in evaluating CDR technologies. There was also a
suggestion not only to consider the economic efficiency of CDR options but also to recognize explicitly the distributional
impacts of certain CDR options, across societal groups as well as across nations or regions.
Suggestions for AR5
It was agreed to discuss the evaluation criteria in a generic manner (CDR broadly rather than specific approaches) and to
focus on the societal aspects (e.g., regulation, acceptability, etc.). Points raised include the following:
AR5 authors may wish to note that published papers almost always refer to operating costs. They often ignore
investment and research and development costs. Often, the market effects of rising prices for large-scale
purchases for geoengineering activities are neglected, and in addition, the external costs of side-effects are not
taken into account. It was highlighted that an assessment of CDR (and also of Solar Radiation Management
(SRM)) may need to go beyond operating costs and look at the ‘full’ economic cost (a term that should be well
defined) for each of the CDR approaches.
One of the important aspects of an assessment of CDR is the choice of a reference case. There are many possible
reference scenarios against which a certain CDR option can be evaluated. It was emphasized that the choice of a
reference scenario by itself is a normative decision and has an important influence on the evaluation of a CDR
option. It was suggested that several scenarios be used as a reference and that the difference in the results
communicated.
The issue of vulnerability or resilience in the context of implementing CDR options was raised. This is an important
issue when certain vulnerable social groups might be affected by CDR. The evaluation of CDR might be considered
within the particular external conditions of the region in which it will be applied. The example of afforestation was
given.
<strong>IPCC</strong> <strong>Expert</strong> <strong>Meeting</strong> on Geoengineering - 86